A new method for rapid computation of transient fuel cycle material balances

This paper develops and demonstrates a fast, medium-fidelity coupled burnup, criticality and fuel cycle mass flow model. The burnup model requires pre-calculated parameters (neutron production and destruction rates, burnup, and isotopic transformation) that are functions of fluence and nuclide. These parameters are specific to a given reactor. It then uses mass-weighted superposition to recombine these parameters as needed and calculate criticality and maximum discharge burnup. This may then be folded in with a piecewise-linear reactivity model to simulate multi-batch cores. The resultant model is then applied to two fuel cycle scenarios: a recyclable uranium cycle and a fast burner reactor cycle. Various fuel cycle parameters are measured, such as isotopics at every stage of the respective fuel cycles. The dynamic and flexible nature of the model allows such fuel cycle data to be quickly recalculated for various initial conditions.